The compact size, low power consumption and no radiation are the major advantages of TFT-LCD. Those advantages make TFT-LCD a dominated technology in the panel display industry and widely adapted in every aspect. The conventional display panel comprises a color filter and an array substrate, wherein R, G, and B color blocks are disposed on the color filter. The color filter on array (COA) substrate is an array substrate with a color filter formed thereon to reduce the light leakage due to the misalignment, lower the capacity coupling between the signal line and the pixel electrode. The aperture rate is increased as well. Therefore, this technology is widely applied on the LCD industry.
However, in the conventional COA substrate, the color filter is thicker, generally with a thickness of several mini-meter. The large contact hole between the signal line and the pixel electrode is required to make sure the electrically contact. Some bubbles would appear because gas would be trapped in the contact hole due to the high aspect ratio of the contact hole during the manufacture process. Moreover, the light leakage is occurred due to the liquid crystal misalignment around the contact hole. The aperture rate is reduced as well. Meanwhile, the electric disconnection occurs because of large slope of the sidewall of the contact hole. This makes the pixel electrode fail to recharge and influence the quality of the liquid crystal display panel.
Therefore, this disclosure discloses a new COA substrate and a manufacturing method to make of to solve the above issues.